Interaction Behaviors of Ce‐Treated Al‐Killed Steel Grades with Different Refractories

Abstract

To understand the effect of the interactions between Ce‐treated steel and refractory on steel cleanliness, the high‐temperature reaction behaviors of Ce‐treated Al‐killed steel with different refractories (MgO, Al2O3, MgO⋅Al2O3, and CeO2) are investigated in laboratory at different times (30–90 min), and the inclusions in steel and the total oxygen contents of the steel are also analyzed. The results show that when the MgO refractory contacts with conventional Al‐killed steel grades, MgO‐Al2O3 spinel is generated as the reacted layer at the boundary; while it reacts with Ce‐treated steel, MgO–Al2O3 spinel is also formed, but it further transforms into Ce2O2S and CeAlO3 with time. In the Ce‐treated steel, CeAlO3 is proved as the stable phase; thus, the reacted layer of CeAlO3 can also be detected at the edges of Al2O3, MgO⋅Al2O3, and CeO2 refractories. Ce treatment leads to more serious degradation of refractory, and the thickness of the reacted layers at the steel–refractory boundary decreases with time due to the spalling of the layer, resulting in the formation of many CeAlO3 macroinclusions in steel and the rise of total oxygen contents of the steel.